Vinyl aromatic hydrocarbons reacted with glyceride oils using boron halide catalyst



United States Patent. Oflice 2,131,430 VINYL AROMATIC HYDROCARBONS nnhc'rnn WITH GLYCERIDE CILS USING BORON I lALIDE CATALYST Henry Brunner, Langley, England, assignor to Imperial Chemical Industries Limited, a corporation of Great Britain 1 No Drawing. Application July 27, 1951, Serial No. 239,025

Claims priority, application Great Britain August 4, 1950.

3 Claims. (Cl. 260-22) This invention relates to interpolymers of vinyl aromatic hydrocarbons and drying oils and to coating compositions containing such interpolymers.

Polymersof vinyl aromatic hydrocarbons are not by themselves very satisfactory film-forming materials. Solutions of the polymers are undesirably viscous and furthermore, films of the polymers have poor weathering characteristics.

The desirability of using the polymers in oleoresinous varnishes has long been recognised but the difficulty has been to obtain a truly compatible combination of the polymers and the most commonly used drying oils, viz. linseed and dehydrated castor.

It is known to obtain polymers of improved compatibility by slow polymerisation of a vinyl aromatic hydrocarbon in the presence of a drying oil. Such reactions may take upwards of 18 hours and if in an attempt to reduce the reaction time, a free radical catalyst such as benzoyl peroxide is used, there is a tendency for the reac tion to run-away resulting in the formation of incompatible products. The tendency for the reaction to runaway may be reduced by adding modifying agents such as a-methyl styrene to the reaction mixture but we have now found that certain types of catalyst will work quite well even in the absence of such modifying agents.

According to the present invention therefore interpolymers are made by reacting a vinyl aromatic hydrocarbon and from 0.1 to 10.0% by weight of the hydrocarbon of a polyhydric alcohol ester of a fatty acid of a drying oil or a partially oxidised or partially polymerised derivative thereof, the reaction being catalysed by a halide of boron.

The reaction mixture may or may not include a solvent but in certain cases, for example where a product of higher molecular weight is required, a solvent may be used.

The invention may be illustrated by reference to the following examples in which all parts are by weight.

Example I To a stirred mixture of 20 parts of linseed oil and 2.2 parts of boron fluoride hydrate heated'to 100 C. was added dropwise 200 parts of styrene. The initial exothermic reaction caused the temperature of the reaction mixture to rise to 130 C. The remaining styrene was added with the temperature more or less constant at 100 C. The styrene addition occupied 90 minutes after which the mixture was heated for a further hour at 100 C. and then taken to 200 C. with CO2 blowing to remove catalyst. No styrene monomer distilled over thus indicating the fixation of all or nearly all of the styrene.

The product, when cool, was a clear soft solid. It was found to be soluble in white spirit, linseed oil, blown linseed oil, 800 poise stand oil and linseed oil-modified alkyd resin (unthinned).

Example II 100 parts of styrene were gradually added to a mixture fiatented Jan. 17, 1956 z. I of 4'pa'rts o'f linseed oil containing 2 parts of boron fluoride hydrate. The experimental procedure was similar to that described in Example' .I. The product was a soft solid resin of acid value 4.7 'mgms; KOH per gm; It was completely miscible with white spirit and linseed oil but largely insoluble in blown linseed oil and linseed stand oil. l'- l Example III The charge. and procedure was as for Example 11 but the varnish linseed oil was replaced by blown linseed oil. The resulting resin was clear and even softer than the product of Example 11. The resin was completely miscible with varnish linseed oil, blown linseed oil and linseed oil-modified alkyd resin.

Example IV Repeating Example III with a styrene/blown linseed oil ratio of;50:l by weight a product was obtained which was a clear viscous liquid of acid value 4.0 mgms. KOH per gm. This liquid resin was similar to the product of Example III in its solubility characteristics.

Example V The procedure described in Example III was adopted for the preparation of polystyrene based on 1000 parts of styrenemonomer and 10 parts of blown linseed oil. The product was a pale viscous liquid of acid value 1.7 mgms. KOH per gm. t

The resin, when cold blended or cooked into drying oils at resinzoil ratios of 1:2, v1:2 and 1:3, gave varnishes soluble in white spirit. Films of these varnishes dried to clear, pale films free from any signs of haze or streakiuess so often associated with styrene-oil copolymer.

Example VI A mixture of 1 part of low viscosity dehydrated castor oil containing 1 part of boron fluoride hydrate was treated with 5 parts of styrene. The temperature rose after a few minutes from 30 C. to 60 C. The mixture was then heated to 100 C. and the remaining .95 parts of styrene gradually added at 100 C. over a period of 45 minutes. After a further one hour at 100 C. the mixture was taken to 200 C. and a stream of CO2 employed to assist in the removal of the catalyst. The product was a sticky solid of acid value 2.2 mgms. KOH per gm. The yield of resin was on the styrene charge; 15 parts of distillate were collected.

Example VII A mixture of 20 parts of benzene, 2 parts of 30 poise linseed stand oil and 2 parts of boron fluoride hydrate were heated to the temperature of reflux (80 C.). The source of heating was then removed and parts of styrene added dropwise to the stirred mixture. The rate of styrene addition was governed by the ensuing exothermic reaction which maintained the mixture at the temperature of gentle refluxing. This reflux temperature gradually rose to 107 C. On the completion of the styrene addition external heating was again applied for 1 hour and the reflux temperature rose to 122 C. The mixture was finally distilled to 200 C. whilst passing a stream of CO2 through the mixture to remove the catalyst and solvent.

The product was a light-brown brittle resin with a melting point of 50 to 61 C.

In general the presence of an inert solvent during the polymerisation process results in a product with a higher melting point and with drying oil-soluble properties simi lar to those of the interpolymers made in the absence of solvent. The higher melting point is advantageous since brittle resins are much easier to handle than are soft, sticky resins.

In the: examples the: catalysts is remo edi by' raisingthe temperature oftthe' reactiorn mixture-@200 and blowing. a stream of an; inert gas,. such as; carbon: dioxide: through it-.. Iahas been: found thatcomglete removal of the catalystthy hlowingiwithzam inentgas at-temgeratures below 1140 is difiicult, possibly, duato the; catalyst being combined in a complex. At temperaturesabo c- 140 C. the catalyst complex will tend to dissociate but an. upper temperature limit to catalyst. removal is set prising an oleoresinous vehicle selected from the group the necessity for avoiding, depoiymerisati'on. of the interpolymer. This will'beginto occur at temperaturesabove Z40' C1 and consequently" the. prefetiredtemper'ature range in which removal of. the catalyst may he carried our. is from 146-240 C;

The interpolymers are a very convenient means of'iir- I troducing styrene into-coating compositions. For example, they may be cooked into oleoresinous vehicles by processes siinil'ar'to thoseused for'rosin"; ortliey niay be incorporated" in alkyd resins during"; polymerisation stage or during the esterificatiow stage ortnay evenhe addedto any drying'oil used in the-- new resin prior to the monoglyceride stage. I

What we claim is:

l. A coating composition forming haze-free films comprising' an oleoresino-us vehicle selected from the group consisting of linseed oil and linseed oil-modified alkyd resin and the interpolymer produced: by reacting amonovinyl rnonocyclic aromatic hydrocarbon with fronrOal to 10 per cent, by weight of the hydrocarbon, ofi a drying oil in the presence of a halide of boron as catalyst:

2. A coating composition forming'haze free filmsrcomconsisting of linseed oil and linseed oil-modified alkyd resin and the interpolymer. groduced by reacting a monovinyl monocyclic aromatic hydrocarbon with from 0.1 to lZO-"Per cent,, l'iy'weightqof the hydrocarbon; oflinseed' oil in the presence of" a halide of Baron as catalyst 3. A coating composition forming haze-free films comprising: an. oleoresinous: vehicle. selected from the group consisting of linseed oil and; linseed oil-modified alkyd resin and the interpolymer produced by reacting a monovinyl monocyclic aromatic hydrocarbon with from 0.1 to 10 per cent, By weight of-tliezhydrocarbon, of a drying oil in the presence of a halide of boron as catalyst, said interpolymerwleoresinmls vehicle. ratio: being from- 1:1 to 1:3.

References; Citidz inithe file. of this. patent UNITED suites PATENTS 2,190,206 Stoesserv a Feb. 20', 1940 2,190,915 sass; Feb. 20, 1940 2.276476 Flint Mar. 10', 1942 2,392,710 Walieford Ian. 18, 1946 21395504 Rulie'ns Feb. 26,1946 2,470,757 Bobalek May 24; 1949 2,567,137 Walte'ford Sept. 4', 1

OTHER.

Hewitt Journal of' Oil and Color Qhemists Association, vol. 29, pages 109-128 Iiine-1946 (pages 118420 ofespecial interest).

Pepper: Quarterlykevi'ews, V111; N0. 1, 1954; pages Sit-93- and 101. 

1. A COATING COMPOSITION FORMING HAZE-FREE FILMS COMPRISING AN OLEORESINOUS VEHICLE SELECTED FROM THE GROUP CONSISTING OF LINESEED OIL AND LINSEED OIL-MODIFIED ALKYD RESIN AND THE INTERPOLYMER PORDUCED BY REACTING A MONOVINYL MONOCYCLIC AROMATIC HYDROCARBON WITH FROM 0.1 TO 10 PER CENT, BY WEIGHT OF THE HYDROCARBON, OF A DRYING OIL IN THE PRESENCE OF A HALIDE OF BORON AS CATALYST. 